This invention has relation to a gas fired broiler which can consistently produce broiled steaks and the like to minutely controlled specifications as to the amount of char or searing and as to the degree of doneness throughout. The invention also has to do with a down firing gas burner useful to produce such steaks; and a method of cooking using a down firing heat source.
It is known to broil meat such as hamburgers between upper and lower gas fired burners. See U.S. Pat. No. 3,604,336 to D. E. Straub, granted Sept. 14, 1971 and U.S. Pat. No. 3,580,164 to E. D. Baker, granted May 25, 1971. These patents show the passing of meat to be broiled along an endless one way conveyor belt. They afford no opportunity for varying the flavor and cooking from piece to piece of the finished product. In fact, uniformity of cooking of the finished product is a major attribute or claim of these patents. Furthermore, where a straight Bunsen burner action is relied upon from the upper burner, that burner has to be positioned so close to the meat that excessive spattering occurs on the burner, and, in numerous instances, the setting is so close that any substantial non-uniformity in the thickness of the product being broiled results in the burner actually touching the top of the product. See U.S. Pat. No. 3,604,336, column 5, lines 10 through 15.
Attempts to elongate the downward flame by increasing pressure of the gas-air mixture result in flame-out due to mixture exceeding a velocity beyond which the flame can cling to the burner.
Downfiring gas burners are used to heat a ceramic plate to radiance. This forms a relatively very slowly controlled heat source, which is incapable of creating anything but one uniformly broiled piece of food after another. See U.S. Pat. No. 3,580,164, column 2, lines 47 through 52 and lines 59 through 65. Such an upper radiant heater must be even more closely spaced to an upper food surface to obtain comparable heating.
It has been suggested to control the heating and cooking of cheese sandwiches, hamburgers, French toast, bacon, pancakes, and the like as they pass along a one-way conveyor between a pair of heat sources by raising and lowering the upper source with respect to the food on the conveyor. See U.S. Pat. No. 3,646,880 to J. D. Norris, granted Mar. 7, 1972. Once this adjustment has been made it is maintained as long as units of a particular uniform product are passing on through the broiler. This vertical adjustment is not useful to vary the cooking and flavor attributes of individual single pieces of steak or the like.